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<head>
	<meta http-equiv="Content-Type" content="text/html;charset=UTF-8">
	<title>Document</title>
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<body>
	<h1>我的第一段 JavaScript</h1>
	<p id="demo">JavaScript 能够直接写入 HTML 输出流中：</p>
	<script type="text/javascript">
		function myFunction(){
			x=document.getElementById("demo");
			x.innerHTML="Hello JavaScript!";
		}
	</script>
	<button type="button" onclick="myFunction()">点击这里</button>
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